CN107027238B

CN107027238B - Component carrier including copper filled multipath laser drilled holes

Info

Publication number: CN107027238B
Application number: CN201610066877.XA
Authority: CN
Inventors: 尼古劳斯·鲍尔·欧平格尔; 陈赵健; 窦玉村; 威廉·塔姆
Original assignee: AT&S China Co Ltd
Current assignee: AT&S China Co Ltd
Priority date: 2016-01-29
Filing date: 2016-01-29
Publication date: 2020-08-18
Anticipated expiration: 2036-01-29
Also published as: CN107027238A; US10701793B2; US20170223820A1; US10278280B2; EP3200570A1; US20190215950A1

Abstract

The invention relates to a component carrier (100) comprising a layer stack (101) of an electrically insulating structure and an electrically conductive structure. Furthermore, the bore (110) extends into the layer stack (101) and has a first bore section (111) and a connected second bore section (112), the first bore section (111) having a first diameter (D1), the second bore section (112) having a second diameter (D2) different from the first diameter (D1). The thermally conductive material (102) substantially fills the entire borehole (110). The bore (110) is formed in particular by laser drilling.

Description

Component carrier including copper filled multipath laser drilled holes

Technical Field

The present invention relates to a component carrier, a component mounting system and an electronic device. The invention further relates to a method for producing a component carrier.

Background

Conventionally, a Printed Circuit Board (PCB) used as a component carrier includes a plurality of drilled holes forming vias for making electrical connections to electrical components. In addition, to reduce the risk of overheating, drilling is used to provide heat transfer.

Each component carrier typically includes a plurality of vias (bores), for example more than one thousand. Therefore, in order to manufacture the component carrier in a short manufacturing time, it is necessary to provide a high-speed drilling forming process. Furthermore, in order to provide adequate connectivity, manufacturing tolerances for the dimensions of the bore holes are allowed to be very small. Therefore, the high speed drilling process must be not only fast but also very accurate.

Conventional bores need to have a small diameter so that the connection pads remain small and the bore has sufficient space in the component carrier. However, small-sized boreholes also have poor heat transfer capabilities.

Modern electronic devices are more tiny and accurate and even have multiple functions, which means that more electronic components must be placed on a compact PCB. In the case of the laser drilling process, the compact size with more components requires smaller laser vias, higher laser via density, tighter line/space designs and smaller capture pad sizes of the pads connected to the vias. However, tighter line/space designs in limited areas result in smaller laser via sizes and connection diameters. Due to laser energy reflection, when the inner layer target Cu (copper) is hit during laser drilling, a protruding section is generated around the via (drill) opening. Standard plating techniques require laser-formed vias with a small aspect ratio AR (length a of the bore/opening diameter R of the bore) typically around 0.8, since otherwise the risk of plating defects such as inclusions and cracks would be significantly increased.

When laser vias with smaller connection (pad) diameters are required on a dielectric PCB with the same thickness in order to avoid misalignment (i.e. the laser via moves to an inner layer pad), the via opening diameter will also have to be reduced, thus causing a higher risk of plating action.

The fact that more and more electronic components are mounted to limited PCB sizes also means higher heat spreading and transfer requirements. About 30% of the drilled holes (vias) that can be formed by laser drilling will be connected to the ground lands and dedicated to the thermal diffusion effect.

Disclosure of Invention

It is an object of the present invention to provide a component carrier that addresses the conflict between the small laser via connection diameter requirement, which is required due to tight design requirements, and the larger laser via opening diameter, which is required to allow reliable plating performance.

This object is solved by the subject matter of the independent claims, in particular by an element carrier.

According to a first aspect of the invention, a component carrier is provided. The component carrier comprises a layer stack of an electrically insulating structure and an electrically conductive structure. Furthermore, the component carrier comprises a bore which extends into the layer stack and has a first bore section with a first diameter and a connected second bore section with a second diameter which is different from the first diameter. The component carrier further includes a thermally conductive material filling substantially the entire bore. The bore hole may in particular be formed by laser drilling.

In the context of the present application, the term "component carrier" may particularly denote any support structure for providing mechanical support and electrical connectivity, on and/or in which one or more electronic components can be accommodated. Exemplary embodiments of the component carrier are described further below.

Furthermore, the bore of the component carrier comprises a first bore section having a first diameter and a second bore section having a second diameter. The first diameter and the second diameter are different from each other. In an exemplary embodiment, the first bore diameter is greater than the second bore diameter.

For example, the first and second drilling sections may be drilled by a laser drilling method, and the first and second drilling sections may have a slightly conical shape. The first diameter may thus be defined by a first average diameter, which is the arithmetic average of the diameter of the first drill section, for example the diameter at the opening of the first drill section, and the diameter of the first drill section taken at the transition of the first drill section to the transition section and/or to the second drill section. Accordingly, the second diameter may be defined by a second average diameter, which is an arithmetic average of the diameter of the second drill section, for example the diameter at the opening of the second drill section, and the diameter of the second drill section taken at the transition of the second drill section to the transition section and/or to the first drill section. Alternatively, the first diameter may represent an opening diameter of the first drilling section at the first surface and the second diameter may represent an opening diameter of the second drilling section at the second surface.

The bore is filled with a thermally conductive material. In addition to suitable thermal conductivity properties, the thermally conductive material may also be electrically conductive. In an exemplary embodiment, the thermally conductive material is copper or a copper compound.

For example, the multi-path bore may be formed by a laser drilling process. A laser drilling process may be used instead of, for example, a standard single diameter drill bit for mechanical drilling. The drill hole according to the present invention may be formed by varying the laser via density, the laser beam cross-sectional area, and the penetration time for penetrating the layer stack with laser radiation.

The bore filled with the thermally conductive material may form a via that serves as a connection between two or more layers within a layer stack of a component carrier (e.g., a printed circuit board). The vias may form through holes, blind holes, or buried holes.

By providing the drill holes with different diameters according to the invention, a small diameter target pad diameter of the pad section made of a heat conducting material and formed at the exit opening section of the drill hole and additionally a better heat transfer through the heat conducting material in the larger (second) drill hole section of the drill hole is achieved.

According to a further exemplary embodiment, the layer stack comprises a first surface and a second surface opposite the first surface, wherein the bore hole extends between the first surface and the second surface.

According to a further exemplary embodiment, the first drill section extends from the first surface into the layer stack and the second drill section extends from the second surface into the layer stack.

According to a further exemplary embodiment, the thermally conductive material forms a pad segment on the second surface. The land segments may be connected to, for example, printed circuit board tracks or the like. Furthermore, the pad segment is part of a thermally conductive material that fills the drilled hole such that a via (vertical connection) through the layer stack is formed. Vias connect other embedded components and conductive layer structures within the layer stack to the pads. The pads typically have a larger diameter than the printed circuit board tracks.

However, it is possible to form the printed circuit board tracks and fill the drilled holes with a thermally conductive material in one single operation step. Thus, the land segments have the same size (width) as the printed circuit board tracks. Thus, a landless connection between the printed circuit board track and the via is possible because no production tolerances are required. Thus, pad-less and so-called "landless" (seamless) via-printed circuit board track connections can be provided.

According to a further exemplary embodiment, a thermally conductive material extends along the first surface for forming the heat radiating section. The larger the heat radiating section along the first surface, the more heat can be transferred away from the component carrier.

According to a further exemplary embodiment, the heat radiating section forms a first cover region on the first surface, and the pad forms a second cover region on the second surface. The first coverage area is larger than the second coverage area.

The object is to have smaller pad segments along the second surface so that a plurality of pad segments and thus a plurality of bores can be formed in the component carrier. The more pad segments that are formed within the component carrier, the more connection possibilities a given component carrier. Therefore, the pad segments should be small to prevent contact with adjacent pad segments. On the other hand, a larger heat radiating section along the first surface is required so that a suitable heat transport away from the element carrier is provided. For example, fewer but larger bores may be formed for heat transfer, but still allowing for smaller capture pad segments with small diameters.

With regard to the size of the heat radiating section, the size of the protruding section of the heat radiating section, which is defined between the outer circumference of the heat radiating section and the edge of the first drill section at the first surface, is limited, because if the protruding section exceeds a certain threshold size, the risk of voids, cracks and other plating defects during the plating process where the heat conductive material flows into the drill hole is increased.

According to a further exemplary embodiment, the element carrier further comprises a further bore hole extending into the layer stack. The further bore is spaced apart from the bore, wherein the further bore extends between the first surface and the second surface. The thermally conductive material is filled substantially throughout the further bore. Further the bore may be formed with a uniform diameter or may be formed from bores having sections of different diameters as described above.

According to a further exemplary embodiment, the thermally conductive material extends along the first surface between the bore hole and the further bore hole. Thus, a common heat radiation section for the borehole and the further borehole can be generated along the first surface. However, the heat radiating section of the bore may be electrically isolated with respect to the further heat radiating section of the further bore.

According to a further exemplary embodiment, a transition section is formed between the first bore section and the second bore section. In the transition section, the first diameter merges into the second diameter. The first diameter is greater than the second diameter. In an exemplary embodiment, the first diameter may be, for example, between about 50 μm (micrometers) to about 300 μm, and particularly between about 70 μm to about 150 μm. Accordingly, the second diameter may be, for example, between about 20 μm and about 100 μm, in particular between about 40 μm and about 80 μm.

The transition section may be defined as a section of larger diameter reduction and merging into a section of smaller diameter. The length of the transition section along the bore axis may be, for example, 1/2-1/15 of the total bore length and thus the total thickness of the element carrier. In particular, the length of the transition section along the drilling axis may be, for example, 1/4 of the total drilling length and thus the total thickness of the component carrier.

According to a further exemplary embodiment, the bore hole has a ramp shape. The bore having a ramp shape comprises, for example, an upper first bore section and a lower second bore section, wherein a transition section is formed between the first bore section and the second bore section.

The first bore section includes a larger diameter than the second bore section. In particular, the first drilling section comprises a slightly conical shape, wherein the first diameter of the first drilling section decreases from the opening section of the first drilling section at the first surface in a direction to the transition section. In a cross-sectional view of the borehole, the wall forming the first borehole section may have a curved shape.

The second bore section includes a smaller diameter than the first bore section. In particular, the second bore section comprises a slightly conical shape, wherein the second diameter of the second bore section decreases from the transition section in a direction to a second open section of the second bore at the second surface. In a cross-sectional view of the borehole, the wall forming the second borehole section may have a curved shape.

The transition section includes a diameter that decreases rapidly along the drilling axis from the first drilling section in a direction to the second drilling section. In a cross-sectional view of the bore hole, the transition section forms an S-shaped path. In exemplary embodiments, the average diameter of the transition section may be, for example, between about 15 μm (micrometers) to about 200 μm, and particularly between about 30 μm to about 100 μm.

In particular, the first drilling section and the second drilling section comprise a common drilling axis. The transition extends in a plane having a normal, wherein the transition is formed such that an angle between the normal and the common borehole axis is about ± 35 degrees and, for example, parallel to the common borehole axis.

In summary, the ramp shape of the bore may actually be considered to be an onion dome shape.

The slope shape of the drilled hole may preferably be formed by laser drilling because the slope shape may be formed by using laser intensity and laser line width.

According to a further exemplary embodiment, the first bore section comprises a first aspect ratio (aspect ratio) which is a ratio between a first length of the first bore section and a diameter of the first bore section at the first surface. The second bore section includes a second length to diameter ratio, which is a ratio between a second length of the second bore section and a diameter of the second bore section at the second surface. The first aspect ratio is less than the second aspect ratio.

The aspect ratio AR is defined by the thickness (length) a of the bore relative to the opening diameter R of the bore at the respective surface of the component carrier:

AR＝A/R

the plating capacity can be increased by a reduction in the aspect ratio AR. The aspect ratio AR can therefore be reduced by reducing the length of the bore and/or increasing the opening diameter R.

Thus, by drilling as described above comprising a first drill section having e.g. a larger diameter than the diameter of a second drill section, the opening diameter R of the first drill section may also be increased in order to provide a large surface of the heat radiating section, wherein the diameter R of the second drill section is reduced in order to provide a small size of the pad section along the second surface.

Further, the first length of the first bore section may be formed to be greater than the second length of the second bore section to provide a suitable length to diameter ratio for the first bore section and the second bore section. For example, the first length may be twice as long as the second length.

For example, in a mechanical drill with a uniform diameter, a stack of layers of an element carrier with a thickness a of 1mm and an opening diameter R of 0.1mm will have a thickness of 10: the aspect ratio AR of 1-10 is A/R.

However, the aspect ratio for the first and second drilling sections is preferably less than about 1, more specifically less than 0.8. The aspect ratios of the first and second drilling sections may be different from each other or may be equal (in particular by adjusting the length and width of the two drilling sections relative to each other). As can be seen from the above examples, the drilling according to the invention comprises a first aspect ratio of the first drilling section and a second aspect ratio of the second drilling section. Thus, the sum of the two aspect ratios may be less than the overall aspect ratio of conventional boreholes.

In summary, the overall aspect ratio of the bore hole is reduced to ease the (copper) plating process. Further, forming the smaller pad section of the second drill section, the internal stress of the component carrier is reduced and the reliability is improved. Furthermore, it may generally be advantageous to keep the impedance within the element carrier constant. However, it is difficult to make the impedance between the heat-conducting member or line of the component carrier and the via constant. With a smaller diameter (e.g. by a smaller second drilling section comprising a second opening diameter), the capacitance will be reduced and the land and pad dimensions may also be reduced, respectively. As described above, "landless" vias may also be formed. Smaller land vias or landless vias also affect capacitance and impedance, respectively. By the interaction of the via diameter and the land (pad size), the impedance can be adjusted and tuned, respectively, so that the impedance difference between the wire and the via can be compensated. A further advantage may be reduced losses. Since the diameter can be reduced, the capacitance is also reduced and thus the charging current is reduced, which respectively results in a reduced charging current.

In particular, by forming the drill hole having a ramp-like shape by using the laser drilling method, it is possible to provide a laser-formed via hole (drill hole) having a larger first opening diameter of the first drill section and a smaller connection diameter (smaller pad section) of the second drill section. With a smaller connection diameter, precise alignment performance of critical capture pads can be achieved. At the same time, a larger opening diameter allows for a smaller aspect ratio AR, which will facilitate the plating process. Thus, a larger first opening diameter provides a larger heat spreading area (i.e. heat radiating section), which means that the number of laser vias used only for heat transfer can be reduced, since the required heat transfer capacity can be provided by vias (drilled holes) formed according to the invention also used for electrical connection and additionally for providing a larger heat transfer capacity.

In summary, by having different sized segments, a suitable aspect ratio limit for the copper fill process is given and seal/small target pad annular ring breaks are prevented. Furthermore, the total volume of copper (used as a thermally conductive material) in the filled vias (drill holes) is increased for better heat transfer. Thus, a small amount of heat stays in the vias, which causes a lower temperature and less expansion of the layer stack. This results in less stress and better reliability of the component carrier.

According to a further exemplary embodiment, the at least one electrically insulating (layer) structure comprises at least one of the group consisting of a resin, in particular a bismaleimide triazine resin, a cyanate ester, a glass, in particular a glass fiber, a prepreg material, a polyimide, a liquid crystal polymer, a Build-Up film (Build-Up film), an FR4 material, a ceramic and a metal oxide. While prepreg or FR4 is generally preferred, other materials may be used.

In an embodiment, the at least one electrically conductive (layer) structure comprises at least one of the group consisting of copper, aluminum and nickel. Although copper is generally preferred, other materials are possible.

In an embodiment, the component carrier is shaped as a plate. This contributes to a compact design of the electronic device, wherein the component carrier nevertheless provides a large basis for mounting the electronic component on the component carrier. Further, in particular, a bare die as a preferred example of an embedded electronic component can be easily embedded in a thin plate such as a printed circuit board because of its small thickness.

In an embodiment, the component carrier is configured as one of the group consisting of a printed circuit board and a substrate.

In the context of the present application, the term "Printed Circuit Board (PCB)" may particularly denote a plate-shaped component carrier which is formed by laminating several electrically conductive layer structures with several electrically insulating layer structures, for example by applying pressure, possibly with the supply of thermal energy. As a preferred material for PCB technology, the electrically conductive layer structure is made of copper, while the electrically insulating layer structure may comprise resin and/or glass fibre, so-called prepreg material or FR4 material. The various conductive layer structures can be connected to each other in a desired manner by forming through-holes through the laminate, for example by laser drilling or mechanical drilling, and by filling with a conductive material, in particular copper, so as to form vias as through-hole connections. In addition to one or more electronic components that may be embedded in a printed circuit board, printed circuit boards are typically configured to receive one or more electronic components on one or both opposing surfaces of a board-like printed circuit board. They may be joined to the respective major surfaces by brazing.

In the context of the present application, the term "substrate" may particularly denote a small component carrier having substantially the same dimensions as the electronic components mounted thereon.

In an embodiment, the component carrier is a laminate type component carrier. In such an embodiment, the component carrier is a composite of a multilayer structure which is stacked and joined together by applying pressure, optionally with heat.

According to a further exemplary embodiment, an electronic device comprises an electronic component with electrical terminals and the above-mentioned component carrier in which the electronic component is encapsulated.

In an embodiment, the electronic component is selected from the group consisting of: active electronic components, passive electronic components, electronic chips, memory devices, filters, integrated circuits, signal processing components, power management components, optoelectronic interface components, voltage converters, cryptographic components, transmitters and/or receivers, electromechanical transducers, sensors, actuators, microelectromechanical systems, microprocessors, capacitors, resistors, inductors, batteries, switches, cameras, antennas, and logic chips. For example, a magnetic element may be used as the electronic element. Such a magnetic element may be a permanent magnetic element (e.g. a ferromagnetic, antiferromagnetic or ferrimagnetic element, such as a ferrite core) or may be a paramagnetic element. However, other electronic components, in particular those that generate and emit electromagnetic radiation and/or are sensitive to electromagnetic radiation propagating from the environment to the electronic component, may be embedded in the electronic device.

According to a further aspect of the invention, a component carrier system is described comprising the above component carrier and additionally the above component carrier. The component carrier is arranged on the further component carrier such that the second bore section of the component carrier adjoins the further first bore section of the further component carrier.

According to a further exemplary embodiment of the system, the second bore section of the bore of the component carrier and the second bore section of the further bore of the further component carrier face each other and the first bore section of the bore of the component carrier and the first bore section of the further bore of the further component carrier face each other.

According to a further exemplary embodiment of the system, the second bore section of the bore of the component carrier and the second bore section of the further bore of the further component carrier are moved laterally relative to each other.

According to a further exemplary embodiment, the system further comprises a high-density layer structure, which is arranged between and electrically and/or thermally coupled with the second bore section of the bore of the component carrier and the second bore section of the further bore of the further component carrier on opposite main surfaces of the high-density layer structure.

According to a further exemplary embodiment of the system, the high-density layer structure is a single-layer structure or a multi-layer structure.

According to a further exemplary embodiment of the system, the electronic component is encapsulated in a high-density layer structure of the component carrier system. By arranging the drill hole and the respective second drill hole section of the further drill hole at the high-density layer structure, a high-density encapsulation and at the same time a good heat transfer away from the high-density layer structure is provided.

According to another aspect of the invention, a method of manufacturing a component carrier is described. According to the method, a layer stack of electrically insulating structures and electrically conductive structures is formed. A borehole is drilled extending to the layer stack, wherein the borehole has a first borehole section with a first diameter and a connected second borehole section with a second diameter different from the first diameter. The entire bore is substantially filled with a thermally conductive material. In particular, the drilling is performed by a laser drilling device.

The aspects defined above and further aspects of the invention are apparent from the examples of embodiment to be described hereinafter and are explained with reference to these examples of embodiment.

The invention will be described in more detail hereinafter with reference to examples of embodiment but to which the invention is not limited.

Drawings

Fig. 1 shows a schematic view of a component carrier comprising a bore with a ramp shape according to an exemplary embodiment of the present invention.

Fig. 2 shows a schematic illustration of a component carrier according to the invention with a bore hole, which is arranged on a further component carrier.

Figure 3 shows a schematic diagram of a defined bore hole for describing aspect ratio.

Fig. 4 shows a schematic view of a component carrier system according to an exemplary embodiment of the present invention.

Fig. 5 shows a schematic view of a further element carrier system according to an exemplary embodiment of the present invention.

Reference mark:

100 element carrier 300 holes

101-layer stack 301 projection

102 thermally conductive material 302 connection segment

103 first surface 303 heat radiation section

104 second surface

105 pad segment

106 heat radiation section 400 component carrier system

107 heat radiation

108 borehole axis 501 high density layer structure

110 bore D1 first diameter

111 first bore section D2 second diameter

112 second drill section L1 first length

113 transition L2 second length

Opening diameter of R bore

120 additional drilling of the thickness of the A-component carrier

121 further pad segment

122 additional heat radiation section

200 additional element carrier

201 additional layer Stacking part

203 further first surface

204 further second surface

205 further pad segment

206 additional heat radiation section

207 contact layer

210 additional drilling of additional component carriers

Detailed Description

The illustration in the drawings is schematically. In different drawings, similar or identical elements are provided with the same reference signs.

Fig. 1 illustrates a component carrier 100, and an electrical component may be embedded in the component carrier 100 or mounted on the component carrier 100. The component carrier 100 comprises a layer stack 101 formed by an electrically insulating structure and an electrically conductive structure and a borehole 110 extending into the layer stack 101 and having a first borehole section 111 and a connected second borehole section 112, the first borehole section 111 having a first diameter D1 and the second borehole section 112 having a second diameter D2 different from the first diameter D1. The component carrier 100 further includes a thermally conductive material 102 that substantially fills the entire bore 110. The bore 110 is formed in particular by laser drilling. In the exemplary embodiment shown in fig. 1, first bore diameter D1 is greater than second bore diameter D2.

The borehole 110 is filled with a thermally conductive material 102. In addition to suitable thermal conductivity properties, thermally conductive material 102 may also be electrically conductive. In an exemplary embodiment, the thermally conductive material 102 is copper or a copper compound.

The bore 110 filled with the thermally conductive material 102 may form a via as a connection between two or more layers within the layer stack 101 of the component carrier 100. By providing the bore 110 with a different diameter D1+ D2, a smaller diameter pad size of the pad segment 105 made of thermally conductive material 102 and formed at the exit section of the bore 110 and additionally better heat transfer through the thermally conductive material 102 within the larger second bore segment 112 of the bore is achieved.

For example, the first and

second drill sections

111 and 112 may be drilled by a laser drilling method, and the first and

second drill sections

111 and 112 may have a slightly conical shape. Thus, the first diameter D1 may be defined by a first average diameter D1, the first average diameter D1 being an arithmetic average of the diameter of the first drill section 111, e.g., the diameter of the opening section of the first drill section 111 and the diameter of the first drill section 111 taken at the transition of the first drill section 111 to the transition section 113 and/or to the second drill section 112. Accordingly, the second diameter D2 may be defined by a second average diameter D2, the second average diameter D2 being an arithmetic average of the diameter of the second drill section 112, e.g., the diameter of the open section of the second drill section 112 and the diameter of the second drill section 112 taken at the transition of the second drill section 112 to the transition section 113 and/or to the first drill section 111.

The layer stack 101 comprises a first surface 103 and a second surface 104 opposite the first surface 103, wherein the bore 110 extends between the first surface 103 and the second surface 104. A first drill section 111 extends from the first surface 103 into the layer stack 101 and a second drill section 112 extends from the second surface 104 into the layer stack 101.

Thermally conductive material 102 forms a pad segment 105 on second surface 104. The pad segments 105 may be connected to, for example, printed circuit board traces. Furthermore, the pad segment 105 is a portion of the thermally conductive material 102 that fills the bore 110 such that a via (vertical connection) is formed through the layer stack 101. Vias connect other embedded components and conductive layer structures within layer stack 101 to pad segment 105. Typically, the pad segments 105 have a diameter that is larger than the diameter of the printed circuit board track. However, it is possible to form the printed circuit board track and fill the bore 110 with the thermally conductive material 102 in a single operation step. Accordingly, the pad segment 105 can be reduced in size and have the same size (width) as the printed circuit board track.

A thermally conductive material 102 extends along the first surface 103 for forming a heat radiating section 106. The larger the heat radiating section 106 along the first surface 103, the more heat 107 can be transferred away from the component carrier 100. The heat radiating section 106 forms a first coverage area on the first surface 103, and the pad section 105 forms a second coverage area on the second surface 104. The first coverage area is greater than the first coverage area.

With respect to the size of the heat radiating section 106, the protruding section 301 of the heat radiating section 105 defined between the periphery of the heat radiating section 105 and the edge of the first drill section 111 at the first surface 103 is limited in size, because if the protruding section 301 exceeds a certain threshold size, the risk of voids, cracks and other plating defects during the plating process where the thermally conductive material 102 flows into the drill hole 110 is increased.

The diameter used to calculate the aspect ratio may be the diameter of the respective open section of the

respective drill section

111, 112 or the above-mentioned average diameter of the

respective drill section

111, 112.

As can be seen from fig. 1, the first drilling section 111 comprises a diameter D1 which is larger than the second diameter D2 of the second drilling section 112. In particular, the first drilling section 111 comprises a slightly conical shape, wherein the first diameter D1 of the first drilling section 111 decreases from the opening section of the first drilling section 111 at the first surface 103 in a direction to the transition section 113. The circumferential area of the conical first drilling section 111 may have a slightly curved shape.

The second bore section 112 includes a diameter D2 that is smaller than the diameter of the first bore section 111. In particular, the second bore section 112 comprises a slightly conical shape, wherein the second diameter D2 of the second bore section 112 decreases from the transition section 113 in a direction to a second open section of the second bore 112 at the second surface 104. The circumferential area of the conical second drill section 112 may have a slightly curved shape.

The transition section 113 comprises a diameter that decreases rapidly along the drilling axis 108 from the first drilling section 111 in a direction to the second drilling section 112. In the sectional view as shown in fig. 1, the transition section forms an S-shaped course.

In particular, the first and

second drill sections

111, 112 comprise a common drill axis 108. The transition 113 extends in a plane having a normal, wherein the transition is formed such that the angle between the normal and the common borehole axis 108 is about ± 35 degrees and, for example, parallel to the common borehole axis 108. In summary, the ramp shape of the bore 110 may actually be considered an onion dome shape.

The first drilling section 111 comprises a first aspect ratio, which is the ratio between the first length L1 of the first drilling section 111 and the diameter D1 (opening diameter) of the first drilling section 110 at the first surface 103. The second drilling section 112 comprises a second aspect ratio, which is the ratio between the second length L2 of the second drilling section 112 and the diameter D2 (opening diameter) of the second drilling section 112 at the second surface 104. The first aspect ratio may be less than the second aspect ratio.

The borehole 110 shown in fig. 1 is designed such that the first borehole section 111 has a diameter D1 which is, for example, larger than the diameter of the second borehole section 112. The opening diameter R (D1) of the first drill section 111 is increased in order to provide a larger surface area 301 of the heat radiating section 106, wherein the diameter R (D2) of the second drill section 112 is decreased in order to provide a small size of the pad section 105 along the second surface 104.

Further, the first length L1 of the first drilling section 111 is formed to be larger than the second length L2 of the second drilling section 112 in order to provide a suitable aspect ratio AR for both the first drilling section 111 and the second drilling section 112. For example, the first length L1 may have twice the length of the second length L2.

First length L1 is defined as the length from first surface 103 to transition section 113 along drilling axis 108. The second length L2 is defined as the length from the second surface 104 to the transition section 113 along the bore axis 108. Half of the length of the transition section is allocated to a first length L1 and the other half of the length of the transition section is allocated to a second length L2.

In particular, by forming the drill hole 110 having a ramp-like shape as shown in fig. 1 using a laser drilling method, a laser formed via hole (drill hole 110) having a larger first opening diameter D1 of the first drill section 111 and a smaller connection diameter D2 (smaller pad section) of the second drill section 112 can be provided. With a smaller connection diameter D2, precise alignment performance of the critical capture pad 105 may be achieved. At the same time, the larger opening diameter D1 of the first bore 110 allows for a smaller aspect ratio AR, which will facilitate the plating process. Therefore, the larger first opening diameter D1 provides a larger heat diffusion area (i.e., the heat radiating section 106).

Fig. 2 shows a schematic illustration of a component carrier 100 according to the invention with a borehole 110 arranged on a further component carrier 200. Alternatively,

reference numerals

100 and 110 in fig. 2 may denote two layers of one and the same board.

The component carrier 100 includes a bore 110 as shown in fig. 1. In particular, the component carrier 100 comprises a layer stack 101 of electrically insulating and electrically conductive structures and a borehole 110 which extends into the layer stack 101 and has a first borehole section 111 and a connected second borehole section 112, the first borehole section 111 having a first diameter D1 and the second borehole section 112 having a second diameter D2 which is different from the first diameter D1. The component carrier further comprises a thermally conductive material 102 that substantially fills the entire bore 110. The bore 110 is formed in particular by laser drilling. In the exemplary embodiment shown in fig. 1, first bore diameter D1 is greater than second bore diameter D2.

Furthermore, as shown in fig. 2, the first bore section comprises a larger heat radiating section 106 such that heat 107 is transferred away from the component carrier 100.

Furthermore, the component carrier 100 comprises a further bore 120 arranged adjacent to the bore 110. Additionally the bore 120 is shown in a conventional uniform and somewhat conical design. As can be seen from fig. 2, the further pad section 121 of the further bore 120 and the further heat radiating section 122 of the further bore 120 comprise almost similar size areas, since a smaller further pad section 121 is not possible due to the larger opening diameter of the further bore 120. In addition, the larger additional heat radiating section 122 is also not easily manufactured due to the plating process requirements.

Furthermore, as can be taken from fig. 2, the component carrier 100 is arranged on a further component carrier 200. The further element carrier 200 comprises further boreholes 210 filled with a thermally and electrically conductive material. Additionally, the bore 210 may be drilled by laser drilling or mechanical drilling methods. The further bore 210 includes a further heat radiating section 206, and the

pad sections

105, 121 of the

respective bores

110, 120 of the component carrier 100 are respectively disposed on the further heat radiating section 206 and are in electrothermal contact with the further heat radiating section 206. Accordingly, the further heat radiating section 206 is formed along the further first surface 203 of the further layer stack 201. The further heat radiating section 206 may comprise a heat conductive material connecting two adjacent further boreholes 210. The further bore 210 may comprise respective further pad segments 205 formed along a further second surface of the further layer stack 201. The further pad segment 205 is in contact with a contact layer 207 arranged on the further layer stack 201.

As can be taken from fig. 2, the further bore 210 of the further component carrier 200 comprises a uniform or conical shape such that the further heat radiating section 206 and the further pad section 205 have almost the same dimensions. In particular, the further heat radiating section 206 of the further component carrier 200 comprises dimensions almost the same as the dimensions of the further pad section 121 of the further bore 120 of the component carrier 100. Therefore, as a high risk of misalignment 208, this is a pad segment movement of the further pad segment 121 and the respective further heat radiating segment 206 of the further bore 210 of the further component carrier 200. In particular, the mismatch alignment 208 describes a movement of the further bore 120 of the component carrier 100 relative to the further bore 210 of the further component carrier 200 such that the thermally conductive material within the further bore 120 forms a protrusion relative to the thermally conductive material within the further bore 210 of the further component carrier 200. The above-described protrusion of the misalignment 108 is highlighted within the circle drawn in fig. 2. Thus, by reducing the pad segments 105 of the drill hole 100 according to the present invention, the risk of misalignment 108 is reduced.

Fig. 3 shows a schematic diagram of a defined bore hole for describing the aspect ratio AR. The aspect ratio AR is defined by the thickness (length) a of the bore 300 relative to the opening diameter R of the bore 300 at the respective surface of the component carrier:

AR＝A/R

the plating capacity can be increased by a reduction in the aspect ratio AR. The aspect ratio AR may be reduced by reducing the length of the bore 300 and/or increasing the opening diameter R.

For example, the stacked layers of the component carrier have a thickness a (which is a drill length) of 50 μm (micrometers) and an opening diameter R of the drill 300 of 60 μm (micrometers), so that an aspect ratio AR of 50:60 ═ 0.8 ═ a/R ═ results. The above values for the thickness relate to the printed circuit board as component carrier. The skilled person will realize that smaller thickness values are suitable for the substrate as component carrier.

With respect to the size of the heat radiating section 303, the protruding section 301 of the heat radiating section 303, which is defined between the outer circumference of the heat radiating section 303 and the edge of the drill section at the first surface, is limited in size, because if the protruding section 301 exceeds a certain threshold size, the risk of voids, cracks and other plating defects during the plating process where the heat conductive material flows into the drill hole is increased.

Accordingly, the projection 301 of the connection section 302 (pad section) defined between the outer periphery of the connection section 302 and the edge of the drill section at the first surface is limited in size.

Fig. 4 shows a schematic view of a component carrier system 400 according to an exemplary embodiment of the present invention. The component carrier system 400 comprises the component carrier 100 described above and the further component carrier 200 described above. Alternatively,

reference numerals

100 and 200 in fig. 4 may denote two layers of one and the same board. The component carrier 100 is arranged on the further component carrier 200 in such a way that the second drill section 112 of the component carrier 100 abuts on the further first drill section of the further component carrier 200. In particular, the pad section 105 adjoins the further heat radiating section 206 of the further bore 210. In particular, the bore 110 of the component carrier 100 and the further bore 210 of the further component carrier 200 are formed similar to the bore 110 shown in fig. 1.

Thus, the

boreholes

110, 210 have a larger

heat radiating section

106, 206 than their

respective pad section

105, 205. Thus, suitable plating characteristics are obtained and the risk of misalignment is reduced.

Fig. 5 shows a schematic view of a further element carrier system 400 according to an exemplary embodiment of the present invention. The component carrier system 400 comprises the component carrier 100 described above and the further component carrier 200 described above. Alternatively,

reference numerals

100 and 200 in fig. 5 may denote two layers of one and the same board.

The high-density layer 501 is arranged between the component carrier 100 and the further component carrier 200. The second bore section 112 of the bore 110 adjoins on a first surface of the high density layer 501 and the second bore section 112 of the further bore 210 adjoins on a second surface of the high density layer 501, wherein the first surface is the opposite side with respect to the second surface of the high density layer 501. In other words, the high-density layer 501 is arranged between the second bore section 112 of the bore 110 and the second bore section of the further bore 210. In particular, a first drill section 105 of the drill hole 110 adjoins on a first surface of the high-density layer 501 and a further pad section 205 of a further board 2010 adjoins on a second surface of the high-density layer 501. The second bore section 112 of the bore 110 of the component carrier 100 and the second bore section 112 of the further bore 210 of the further component carrier 200 face each other while the first bore section 111 of the bore 110 of the component carrier 100 and the first bore section 111 of the further bore 210 of the further component carrier 200 face each other.

Furthermore, as can be seen from fig. 5, the second bore section 112 of the bore 110 of the component carrier 100 and the second bore section 112 of the further bore 210 of the further component carrier 200 are laterally displaced relative to one another. By arranging the drill hole 110 and the respective second drill hole section 112 of the further drill hole 210 in the high-density layer structure 501, a high-density encapsulation and at the same time a good heat transfer away from the high-density layer structure 501 is provided.

It should be noted that the term "comprising" does not exclude other elements or steps, and the "a" or "an" does not exclude a plurality. Also elements described in association with different embodiments may be combined. It should also be noted that reference signs in the claims shall not be construed as limiting the scope of the claims. The practice of the invention is not limited to the preferred embodiments shown in the drawings and described above. On the contrary, many variations are possible using the illustrated solutions and in accordance with the principles of the invention, even in the case of fundamentally different embodiments.

Claims

1. A component carrier system (400), comprising:

element carrier (100) comprising:

a layer stack (101) composed of an electrically insulating structure and an electrically conductive structure;

a bore (110) extending into the layer stack (101) and having a first bore section (111) and a connected second bore section (112), wherein the first bore section (111) has a first diameter (D1) and the second bore section (112) has a second diameter (D2) different from the first diameter (D1); and

a thermally conductive material (102) filling substantially the entire borehole (110);

further element carrier (200) comprising:

a further layer stack (101) consisting of a further electrically insulating structure and a further electrically conductive structure;

a further bore (110) extending into the further layer stack (101) and having a further first bore section (111) and a connected further second bore section (112), wherein the further first bore section (111) has a further first diameter (D1), the further second bore section (112) has a further second diameter (D2) different from the further first diameter (D1); and

further thermally conductive material (102) filling substantially the entire borehole (110);

wherein the second bore section (112) of the bore (110) of the component carrier (100) and the second bore section (112) of the further bore (210) of the further component carrier (200) face each other while the first bore section (111) of the component carrier (100) and the first bore section (111) of the further component carrier (200) are opposite each other;

a high-density layer structure (501) which is arranged between the second drilling section (112) of the drilling (110) of the component carrier (100) and the further second drilling section (112) of the further drilling (210) of the further component carrier (200) on opposite main surfaces of the high-density layer structure (501) and which is electrically and/or thermally coupled to the second drilling section (112) of the drilling (110) of the component carrier (100) and the further second drilling section (112) of the further drilling (210) of the further component carrier (200) on opposite main surfaces of the high-density layer structure (501).

2. The component carrier system (400) of claim 1,

wherein the layer stack (101) comprises a first surface (103) and a second surface (104) opposite to the first surface (103),

wherein the bore (110) extends between the first surface (103) and the second surface (104).

3. The component carrier system (400) according to claim 2,

wherein the first drill section (111) extends from the first surface (103) into the layer stack (101) and the second drill section (112) extends from the second surface (104) into the layer stack (101).

4. The component carrier system (400) according to claim 2 or 3,

wherein the thermally conductive material (102) forms a pad segment (105) on the second surface (104).

5. The component carrier system (400) of claim 4,

wherein the thermally conductive material (102) extends along the first surface (103) for forming a heat radiating section (106).

6. The component carrier system (400) of claim 5,

wherein the heat radiating section (106) forms a first footprint on the first surface (103), the pad section (105) forms a second footprint on the second surface (104),

wherein the first coverage area is larger than the second coverage area.

7. The component carrier system (400) according to claim 2, further comprising:

a further bore (120) extending into the layer stack (101),

wherein the further bore (120) is spaced apart from the bore (110),

wherein the further bore (120) extends between the first surface (103) and the second surface (104),

wherein the thermally conductive material (102) substantially fills the entire further bore (120).

8. The component carrier system (400) of claim 5,

wherein the thermally conductive material (102) extends along the first surface (103) between the bore (110) and the further bore (120).

9. The component carrier system (400) according to claim 2,

wherein the first drilling section (111) comprises a first aspect ratio being the ratio between a first length (L1) of the first drilling section (111) and a diameter (D1) of the first drilling section (111) at the first surface (103),

wherein the second drilling section (112) comprises a second aspect ratio, which is the ratio between a second length (L2) of the second drilling section (112) and a diameter (D2) of the second drilling section (112) at the second surface (104), and wherein the first aspect ratio is smaller than the second aspect ratio.

10. The component carrier system (400) of claim 1,

wherein a first diameter (D1) of the first drilling section (111) is larger than a second diameter (D2) of the second drilling section (112).

11. The component carrier system (400) of claim 1,

wherein a transition section (113) is formed between the first drilling section (111) and the second drilling section (112),

wherein in the transition section (113) the first diameter (D1) merges into the second diameter (D2).

12. The component carrier system (400) of claim 1,

wherein the bore (110) has a ramp shape.

13. The component carrier system (400) of claim 1,

wherein the bore (110) is formed by laser drilling.

14. The component carrier system (400) of claim 1,

wherein the at least one electrically insulating structure comprises at least one of a resin, glass, prepreg material, liquid crystal polymer, FR4 material, ceramic, and metal oxide.

15. The component carrier system (400) according to claim 14,

wherein the resin is bismaleimide triazine resin, cyanate ester, polyimide or epoxy-based build-up film and the glass is fiberglass.

16. The component carrier system (400) of claim 1,

wherein the at least one conductive structure comprises at least one of the group consisting of copper, aluminum, and nickel.

17. The component carrier system (400) of claim 1,

wherein the component carrier (100) is shaped as a plate.

18. The component carrier system (400) of claim 1,

wherein the component carrier (100) is configured as a printed circuit board.

19. The component carrier system (400) of claim 1,

wherein the component carrier (100) is a laminate type component carrier (100).

20. The component carrier system (400) according to claim 1, wherein the second bore section (112) of the bore (110) of the component carrier (100) and the second bore section (112) of the further bore (210) of the further component carrier (200) are laterally displaced with respect to each other.

21. The component carrier system (400) according to claim 1, wherein the high-density layer structure (501) is a single-layer structure or a multi-layer structure.

22. An electronic device, the electronic device comprising:

an electronic component having electrical terminals;

the component carrier system (400) according to any of claims 1-21, the electronic component being encapsulated in the component carrier system (400).

23. The electronic device according to claim 22, wherein said electronic components are encapsulated in a high-density layer structure (501) of said component carrier system (400).

24. The electronic device of claim 22 or 23,

wherein the electronic component is selected from the group consisting of an active electronic component and a passive electronic component.

25. The electronic device of claim 22 or 23,

wherein the electronic component is selected from the group consisting of an electronic chip, a memory device, a filter, an integrated circuit, a signal processing component, a power management component, an optoelectronic interface component, a voltage converter, a cryptographic component, a transmitter and/or receiver, an electromechanical transducer, a sensor, an actuator, a microelectromechanical system, a microprocessor, a capacitor, a resistor, an inductance, a battery, a switch, a camera, an antenna, and a magnetic component.

26. The electronic device of claim 25, wherein the electronic chip comprises a logic chip.